Molecular sieve materials, both natural and synthetic, have been demonstrated in the past to be useful as adsorbents and to have catalytic properties for various types of organic conversion reactions. Certain molecular sieves, such as zeolites, aluminophosphates, and mesoporous materials, are ordered, porous crystalline materials having a definite crystalline structure as determined by X-ray diffraction. Within the crystalline molecular sieve material there are a large number of cavities which may be interconnected by a number of channels or pores. These cavities and pores are uniform in size within a specific molecular sieve material. Because the dimensions of these pores are such as to accept for adsorption molecules of certain dimensions while rejecting those of larger dimensions, these materials have come to be known as “molecular sieves” and are utilized in a variety of industrial processes.
Molecular sieves identified by the International Zeolite Association as having the framework type AFX are known. For example, the zeolite known as SSZ-16 is a known crystalline AFX framework type material.
U.S. Pat. No. 4,508,837 discloses zeolite SSZ-16 and its synthesis in the presence of a structure directing agent derived from 1,4-di(1-azoniabicyclo[2.2.2]octane) lower alkane compounds.
U.S. Pat. No. 5,194,235 discloses the synthesis of zeolite SSZ-16 in the presence of DABCO-Cn-diquat cations, where DABCO represents 1,4-diazabicyclo[2.2.2]octane and n is 3, 4 or 5.
R. H. Archer et al. (Micropor. Mesopor. Mater. 2010, 130, 255-265) disclose the synthesis of an aluminosilicate AFX framework type zeolite using 1,3-bis(1-adamantyl)imidazolium cations as a structure directing agent.
The commercial development of SSZ-16 has been hindered by the high cost of these structure directing agents and hence there has been significant interest in finding alternative, less expensive structure directing agents for the synthesis of SSZ-16.
According to the present disclosure, it has now been found that the organic dications described herein are effective as structure directing agents in the synthesis of SSZ-16.